Container for liquefied gas



Dec. 16, 1958 H. WJALTMAN ET AL 2,864,527

CONTAINER FOR LIQUEFIED GAS 2 Sheets-Sheet 1 Filed Dec. 10, 1956INVENTOR. HOWAR D W. ALT MAN.

ATTORN EYS Dec. 16, 1958 H. w. ALTMAN ETAL 2,864,527

CONTAINER FOR LIQUEFIED GAS Filed Dec. 10, 1956 2 Sheets-Sheet 2 l\ \q llllllllll T N l llllllllll O a R i\ IN VEN TOR. HOWARD W. ALTMAN.

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AT TO R N EYS nited J CONTAINER FOR LIQUEFIED GAS Application December10, 1956, Serial No. 627,412

3 Claims. (Cl. 220-14) This invention relates to apparatus for storingliquefied gases having boiling point temperatures materially below 273degrees Kelvin.

In storing liquefied gases at low temperatures, insulated storagevessels are utilized, which vessels include a container for the liquidbeing stored surrounded by an airtight jacket spaced from the outer wallof the container. The air is exhausted from the space, and suitableinsulating material may be placed therein, to form an insulating meanswhich surrounds the container and shields same from heat leakage fromthe environment.

The present invention provides an improved vessel construction of theabove described type that provides novel passage means for access to theinterior of the inner container of the vessel without breaking thevacuum in the sealed insulating space between the inner container andthe surrounding jacket. In general, the construction of the vessel ofthe present invention includes two aligned openings through the wallmeans of the inner container and the jacket, respectively. The openingsare each provided with a removable closure and are connected by apassage through the insulating space. Such passage is formed by a thinwalled cylindrical member that is longitudinally flexible to adapt sameto elongate and contract responsive to variations in the space betweenthe inner container and the jacket, said variations being caused bythermally imposed expansion and contraction of the vessel.

The thin walled cylindrical member forming the confines of the accesspassage has its inner end in sealed connection with the wall of theinner container means and its outer end in sealed connection with thejacket to form a passage that is completely sealed from the surroundingevacuated insulating space. Hence when the outer closure is removed fromthe opening through the jacket the vacuum of the insulating space willnot be broken, and when the inner closure for the opening though thewall of the inner container is removed a Workman can pass through theopenings and the passage connecting same and thereby gain access to theinterior of the inner container.

It is therefore an object of the present invention to provide a vesselfor storing a liquefied gas which vessel incorporates an evacuatedinsulating space surrounding an inner container means, and which vesselis provided with novel means for gaining access to the interior of thecontainer means without disturbing the vacuum of the evacuatedinsulating space.

It is another object of the present invention to provide a storagevessel for a liquefied gas which vessel incorporates novel accesspassage means through inner and outer wall means separated by aninsulating space, said access passage means being normally sealed fromthe enviroment yet provided with safety means for releasing gas from theaccess passage to prevent the buildup of pressure therein in the eventleakage should occur from the container means to the access passage.

2,864,527 Patented Dec. 16, 1958 It is still another object of thepresent invention to provide a storage vessel of the type described thatmcorporates novel access passage means that is maintained sale againstpressure build-ups yet which is maintained' tion will be apparent fromthe following description,

- to annular member 36 at 59.

references being had to the accompanying drawings wherein a preferredform of embodiment of the invention is clearly shown.

In the drawing: 4

Figure 1 is an elevational view of a typical storage vessel for aliquefied gas having a boiling point temperature materially below 273degrees Kelvin at atmospheric pressure, said vessel being provided withthe novel access passage means of the present invention;

Figure l-A is an end sectional view of the vessel of Figure l, thesection being taken along the line 1-A- 1-A of Figure 1; and

Figure 2 is a sectional view through the access passage of the vessel ofFigure 1, the section being taken along a vertical plane through thecenterline of the vessel.

Referring in detail to the drawing, Figures 1 and 1-A illustrate avessel for storing a volatile liquefied gas such as liquid nitrogen. Thevessel is indicated generally at 20 and includes an outer shell 21 thatsurrounds an evacuated insulating space 22. The vessel further includessuitable supports 23 and 24 and is provided with an access passage meansconstructed according to the present invention and indicated generallyat 26.

As is best seen in Figure 2 the construction of access passage means 26includes an outer closure 27 provided ViLh a handle 28. Closure 27 isremovably fastened to annular member 30 by a plurality of bolts 31 andnuts 32, and a suitable seal such as a gasket 34 is interposed betweenconfronting surfaces of closure 27 and annular member 30. The annularmember 30 is welded to a second annular member 36 at 37, the latterbeing extended through a hole in jacket 21 and welded thereto at 39 and40.

An inner closure 42 is provided with a handle 43 and is removablysecured to annular member 44 by a plurality of studs 45 and nuts 46. Asuitable seal such as a gasket 47 is provided betweeninner closure 42and annular member 44, the latter being mounted in a hole through thewall 48 of an inner container indicated gen erally at 49, such innercontainer being the means for directly confining the liquefied gas beingstored. Annular member 44 is secured to the wall 48 at the welds .50 and51.

With continued reference to Figure 2, the confines of access passage 26is formed by a thin walled tubular member indicated generally at 54 andprovided with successive portions 55 and 56 which extend laterally ofthe axis of passage 26 in opposite directions so as to make the thinWalled member 54 longitudinally expandable when inner container 49undergoes thermally imposed radial contraction when it is filled withthe cold liquid to be stored. It will be understood that inner wall 48is cooled to a lower temperature and at a much faster rate as comparedto the outer jacket 21. When the cold liquid being stored is removedfrom inner container 49 the thin walled member 54 will readily compresswhen wall 48 moves outwardly under thermally imposed radial expansion ofinner container 49.

As seen in Figure 2, an annular bracket 58 is welded A thin annularmember 61 is interposed between the upper end portion 62 of thin Walledmember 54 and bracket 58 and a weld 63 secures end portion 62 and thinannular member 61 to the bracket. It has been found that by utilizingthin annular member 61 in this manner the end portion 62 of thin walledmember 54 is prevented from being burned during the formation of weld63.

The lower end portion 65 f thin walled member 54 is welded to a thinannular member 66 at 67 to prevent burning of such lower end portion 65which burning would occur werethe thin lower end portion 65 weldeddirectly to the thick annular member 44. Thin annular member 66 is inturn welded to a thin upstanding shoulder 70 on annular member 44 at theweld 71 and thin annular member 66 and end portion 65 are therebyprevented from being burned and damaged during the formation of thesealed junction between thin walled member 54 and inner container 49.

In the event any leakage of liquid or gas occurs at the junction ofinner closure 42 and annular member 44, there would be a pressurebuildup in access passage 26 which could gradually increase, even whereleakage is slight, to the point where dangerous pressures would bepresent in access passage 26. To eliminate the danger of any suchpressure development a pressure relief means 74 is provided between theinterior of passage 26 and the environment. Such pressure relief meanscan be mounted in a hole 75 through outer closure 27 and may be formedby a casing 76 which houses a ball 75 urged towards closure of a passage77 by a relatively light spring 78. In the event pressure starts tobuild up in access passage 26 the ball 75 will be moved from its seat bythe force exerted on the ball by the gas and such gas will escapethrough outlet 79 to the environment. Due to the unidirectional flowcharacteristic of pressure relief means 74, air from the environmentwill at all times be prevented from entering sealed access passage 26.That is, access passage 26 is prevented from breathing and the formationof frost and ice in passage 26, from condensed moisture in the air ofthe environment, is at all times prevented.

It has been found preferable to form thin walled mem ber 54 of ametallic sheet material of low thermal conductivity to maintain the heatleakage from the environment to a minimum. An austenitic type ofstainlesssteel sheet, known to the trade as Series 300, and of athickness of approximately .038 of an inch has been found to be idealfor the formation of thin walled member 54.

In operation, when the vessel is filled with a cold liquefied gas, bysuitable conduit means and apparatus not illustrated, inner container 49will contract radially relative to outer shell 21 and thin walled member54 will expand as required without imposing damaging stresses on thesealed junctions at its end terminations. If it is desired to gainaccess to the interior 81 of container 49 the liquefied gas is removedtherefrom, by suitable conduits and apparatus not illustrated, and whenthe inner container 49 expands radially the thin walledmember 54 will becompressed as required and-the sealed end connections thereof will at notime be subjected to excessive stresses that would otherwise break thesealed junctions. The outer closure 27 is next removed, and then theinner closure 42 whereby a workman can enter the interior 81 ofinnercontainer 49 by lowering himself through the access passage 26.After the workman has finished and has climbed out of the container theclosures 42 and 27 are replaced and the inner container 49 is ready toagain be filled with the cold liquefied gas. It will be understood thatthe vacuum of evacuated space 22 will at no time be disturbed by theabove described operations and the expense and expenditure of timenormally required to reevacuate the insulating space 22 is therebyavoided.

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

We claim:

1. In an arrangement for storing a liquefied gas having a boiling pointtemperature materially below 273 K. at atmospheric pressure, a manholestructure comprising, in combination: a container for the liquid beingstored having an inner wall formed with a first opening, a jacket inspaced relationship with said container and having an outer wall formedwith a second opening in registry with the first-mentioned opening, thefirst-mentioned opening being located inwardly of said outer wall, saidtwo walls forming an evacuated-insulating space; a flexible channelmember extending between said openings and in a direction transverse tosaid walls and defining an unobstructed manhole passage for providingaccess to the interior of said container, said flexible member isbounded by said evacuated insulation space and being secured in sealedrelationship to said walls in such a manner as to preserve theevacuation of said space, a first cap removable to permit access to theinterior of the vessel but normally positioned inwardly of said outerwall to close the opening of the inner wall, whereby said first capprevents liquefied gas being stored under pressure in said containerfrom contacting said flexible member, and a second cap removable toprovide access to the interior of the flexible channel and to the firstcap but normaly positioned to close the outer opening, whereby thesecond cap supplements the insulating efiect of the first cap andprotects the first cap and the interior of the flexible member fromatmospheric conditions.

2. The arrangement for storing liquefied gas as defined in claim 1,wherein said second cap includes a pressure relief valve.

3. In an arrangement for storing a liquefied gas having a boiling pointtemperature materially below 273 K. at atmospheric pressure, a manholestructure comprising, in combination: a container for the liquid beingstored having an inner wall formed with a first opening, a jacket inspaced relationship with said container and having an outer wall formedwith a second opening in registry with the first-mentioned opening, thefirst-mentioned opening being located inwardly of said outer wall, saidtwo walls forming an evacuated-insulating space; a flexible channelmember extending between said openings and in a direction transverse tosaid walls and defining an unobstructed manhole passage for providingaccess to the interior of said container, said flexible member isbounded by said evacuated insulation space and being secured in sealedrelationship to said walls in such a manner as to preserve theevacuation of said space, a first cap having a diameter less than thediameter of the flexible member, removable to permit access to theinterior of the vessel but normally positioned inwardly of said outerwall to close the opening of the inner wall, whereby said first capprevents liquefied gas being stored under pressure in said containerfrom contacting said flexible member, and a second cap removable toprovide access to the interior of the flexible channel and to the firstcap but normally positioned to close the outer opening, whereby thesecond cap supplements the insulating eifect of the first cap andprotects the first cap and the interior of the flexible member fromatmospheric conditions, and permits said flexible member to be repairedby removing the outer cover while the inner cover holds the liquefiedgas in the inner container.

References Cited in the tile of this patent UNITED STATES PATENTS2,290,038 Folmsbee .July 14, 1942 2,349,137 Brown May 16, 1944 2,776,776Strong et al. Jan. 8, 1957 2,777,295 Bliss et a1 Jan. 15, 1957

